Tuesday, April 30, 2013

Two boards built

I've gotten two of the four boards for the drawbot built and sort-of working.  The top one is the controller for the pen carrier.  It will receive commands over the RS-485 bus (through the big black jack) and drive a servo through the 3-pin header.  The six pin header at the top is for in circuit programming the pic16f1823 micro, and the two pin header is for power.

The bottom board is the usb to RS-485 bridge I prototyped.  This version just has some indicator LEDs.  One for power and two more for data reception and transmission.

Now it's time to work on the software to get the two boards to talk back and forth. Oh happy happy joy joy!!

Monday, April 29, 2013

Green Boards Comin Outa Ma Ears

All my Drawbot boards arrived from the fabricator today.  Time to go by a bigger magnifier and get to building!

This is the communications board that converts USB to RS-485.

This is the board for the pen carrier.  It takes RS-485 in, and drives a servo to accomplish the pen up/down.

And this is the winch board.  It takes RS-485 in, and drives a 2 phase bi-polar stepper motor.

Thursday, April 25, 2013

Yet Another Particle-Bot Prototype

Here's another Particle-Bot prototype.  This one is a lot closer to how I see the final robot.  Using pager motors without a gearbox really cuts down on the unit cost, but to really be able to evaluate the design I need to build a better chassis.  I'm currently thinking 3D printing would be a good choice.

Two Particle-Bots, and two programmers, two nights work.

Tuesday, April 23, 2013

Another particle-bot prototype

Well, I couldn't wait to get a real chassis for my new Particle-Bot boards, so in about 20 minutes I put together this prototype - made form really cool purple cardboard.  

Here's a really crappy video of the 'bot programmed for light seaking

Monday, April 22, 2013

Particle-Bot boards delivered

One of my favorite books of all time is Vehicles: Experiments in Synthetic Psychology by Valentino Braitenberg.  It describes a series of robots controlled using small networks of synthetic neurons, and how  with just a few neurons very complex behaviors can emerge.  Complex enough in fact to be ascribed anthropomorphic labels such as fear, shyness, and indecision.  This book is the inspiration for my latest robot, somewhat appropriately named Particle-bot because it's small, and I happen to like the group They Might be Giants, and their song Particle Man.

This is a shot of the prototype Particle-Bot.  It's built with small gear motors, a small Li-Po battery, and boards I fabricated and built up.  The chip is an ATTiny85 processor, so the software is written using the Arduino IDE, and it programmed using an Arduino with minimal supporting circuitry, and software from here.

After getting the prototype up and going, I refined the board layout, added some other bits, and sent the boards here to get them commercially produced.  The Eagle files for the board are available here.  Today the boards arrived in the mail - YEAH!!

Here's a shot of the front & back of the board.  The maximum size for the boards in the order I made was two inches by two inches.  Because Particle-Bot is so small, I was able to fit the main board, and the "eye stalks", as well as two other boards that implement the ATTiny programming circuit for the Arduino.

Here's the boards cut apart into the the five pieces.  I used my jeweler's saw to cut them apart, and I'm not too great at straight lines with it, but you get the idea. The sixth piece (the thinnest) is waste.

So here's a picture all the boards built up, ready to go to work. The two boards connected together with the twisted wires are the programming circuit.

And this is how it fits on top of an Arduino Duemilenove clone.  I'll be working on a tutorial on how to setup and use the programmer real soon now.

I'm still working on a design so the chassis of the robot can be 3D printed, so seeing the 'bot completely built out and running will have to wait until that's done.